Abstract: ZnS decotrated onto reduced graphene oxide(RGO) composite (ZnS/RGO) had been synthesized through one-step in-situ solvothermal reaction using ZnAc₂ and graphene oxide as reaction precursor and dimethyl sulfoxide (DMSO) as a source of sulfur and reaction solvent. SEM、XRD、Raman and fluorescence spectroscopy had been used to characterize microtopography and chemical structure of ZnS and ZnS/RGO. The results show that the ZnS/RGO composite synthesized through in-situ reaction consists of uniformly decorated spherical ZnS particles and 6-7 layer-structured RGO sheets. Under the simulated ultraviolet irradiation, the photocatalytic results for methyl orange pollutants show that the degradation ratio of ZnS/RGO hybrid is remarkly higher than that of pure ZnS. During the recycling degradation process photocatalytic efficiency of ZnS/RGO remain stable, which demonstrates in-situ reaction enhance the interaction between ZnS and RGO. Fluorescence spectroscopy result shows enchanced photocatalytic degradation efficiency of ZnS/RGO hybrid is mainly attributed to in-situ incorporation of ZnS with RGO sheets, which can efficiently transfer the excited photoelectrons from ZnS to conjugated graphene structures, and further enlarges recombination efficiency of photogenergated electron-hole.